Runarsson joined the Gunners from French club Dijon in the summer of 2020, playing six times over the course of the following season.
Four of those appearances came in the Europa League, before he was replaced for the knockout rounds, with the team ultimately making it to the semi-finals.
The season after, he was sent on the first of his three loan spells, to Leuven in Belgium. He would join Turkish side Alanyaspor in the next campaign, before moving to Cardiff last August.
Having only played eight times for the Bluebirds, he returned to Arsenal this month, and head coach Mikel Arteta has decided that he is not part of his plans.
The 28-year-old is expected to sign for Danish club Copenhagen on a free transfer, according to Bold.dk, where he will compete with former Liverpool youngster Kamil Grabara for the starting position.
Could Ramsdale leave Arsenal?
Aaron Ramsdale will not be leaving Arsenal during the January transfer window, as FootballTransfers understands that Arteta wants to keep him at the Emirates Stadium for the foreseeable future.
The Gunners signed David Raya from Brentford in the summer, which FootballTransfers exclusively revealed would see the Spaniard claim the No.1 spot.
Wishing you all the best, Alex 💪
— Arsenal (@Arsenal) February 1, 2024
With Ramsdale relegated to second string, there had been strong speculation that he could leave in January.
However, even though Arsenal have been approached by numerous clubs, they have not participated in negotiations.
Arteta has told the England international that he wants him to stay and fight for his place.
The Gunners boss wants to have two quality goalkeepers in his squad, similar to Premier League rivals Manchester City, who have Ederson and Stefen Ortega.